I would be interested in contributing code to something like this because things like scripting can be added, and maybe it would move away from Unreal’s editor to something much more suited to modding the game content that’s already working; previewing item model or AI changes ingame; that sort of thing. It could be a totally different tool. And this would not just be about needing it to be free, but making something more suited to modding from the beginning. But I do also feel that this is a waste of time when the same stuff can just be added to, or already exists in, UE4 as it is.
What are the general requirements for a mod? I really don’t know. If there was a few case study articles to read, maybe it would become clearer. One of the major problems with Skyrim for me was that mods couldn’t interface with one another as they’re packaged into files that overwrite the engine code in-order, meaning you have to add them carefully so as not to break other mods (race mods went earlier on in the list, and there is even a tool to sort them for you). If instead mods could be dynamically loaded and inter-tested to show the program user what is working and what’s not been integrated or modified in the game, then that’s very powerful as it allows you to build mod cross-compatibility. Now, simple features like this would then help to legally distance and justify the “mod tool” from the Unreal Editor.
For procedural games like mine, modding environments could just be changing the rules in the text files. But what if another animation is needed? The features like animation previewing can and should be, I think, branched off as separate small apps so you can have, plainly, a model viewer, animation viewer/previewer with editing controls and so on as other free modding tools, even just to encourage people to mod the game if they still have to pay for UE4 at this stage for games that ship in the next few months. It might be possible for my final game to just accept replacement 3d animation uasset’s from the current UE4 editor, in which case anyone in a mod community only has to export plain Max/Maya animation clips and have someone else, a licensee, add a blend system in Unreal Editor and export for the game, which is what I’d want to do for others if I got excited about their modelling skills. I can see it happening.
Correct me if I’m wrong, but weapons and static models could mostly be a simple FBX import. Your game code can do whatever it wants and share this code with external programs. The game or a “mod tool” could preview the different weapon configurations like fire rate and kickback before you swap in the new actual model. FBX import is not difficult to add for an experienced programmer, so you could always outsource the development to another programmer if you want to contribute something like this to the entire UE4 licensee community! And my budget might allow for this which is what excites me. There may be open source level editors, for which calls to your game code can be done over UDP/networking so it’s still a legal way to link applications up to sync the runtime game with a level editor, as long as you don’t use networking communication for the Engine Tools classes like the currenly internal-only (I think?) FBX import.